Depth-of-Knowledge (DOK) Levels for Science
According to Norman L. Webb, Wisconsin Center for Educational Research (“Depth-of-Knowledge
Levels for Four Content Areas,” March 28, 2002), “interpreting and assigning Depth-of-Knowledge
Levels to both objectives within standards and assessment items is an essential requirement of alignment
analysis. Four levels of Depth-of-Knowledge are used for this analysis.” Norman Webb’s “Depth-ofKnowledge Levels for Four Content Areas” include: Language Arts (Reading, Writing), Mathematics,
Science, and Social Studies.
A general definition for each of the four (Webb) Depth-of-Knowledge levels is followed by Table 1,
which provides further specification and examples for each of the DOK levels. Webb recommends that
large-scale, on-demand assessments in reading should only assess Depth-of-Knowledge Levels 1, 2, and
3. Depth-of-Knowledge at Level 4 in science should be reserved for local assessment only.
Descriptors of DOK Levels for Science (based on Webb and Wixson, March 2002)
Level 1 Recall and Reproduction requires recall of information, such as a fact, definition, term, or a
simple procedure, as well as performing a simple science process or procedure. Level 1 only requires
students to demonstrate a rote response, use a well-known formula, follow a set procedure (like a recipe),
or perform a clearly defined series of steps. A “simple” procedure is well-defined and typically involves
only one-step. Verbs such as “identify,” “recall,” “recognize,” “use,” “calculate,” and “measure”
generally represent cognitive work at the recall and reproduction level. Simple word problems that can be
directly translated into and solved by a formula are considered Level 1. Verbs such as “describe” and
“explain” could be classified at different DOK levels, depending on the complexity of what is to be
described and explained.
A student answering a Level 1 item either knows the answer or does not: that is, the answer does not need
to be “figured out” or “solved.” In other words, if the knowledge necessary to answer an item
automatically provides the answer to the item, then the item is at Level 1. If the knowledge necessary to
answer the item does not automatically provide the answer, the item is at least at Level 2.
Level 2 Skills and Concepts includes the engagement of some mental processing beyond recalling or
reproducing a response. The content knowledge or process involved is more complex than in level 1.
Items require students to make some decisions as to how to approach the question or problem. Keywords
that generally distinguish a Level 2 item include “classify,” “organize,” ”estimate,” “make observations,”
“collect and display data,” and “compare data.” These actions imply more than one step. For example, to
compare data requires first identifying characteristics of the objects or phenomenon and then grouping or
ordering the objects. Level 2 activities include making observations and collecting data; classifying,
organizing, and comparing data; and organizing and displaying data in tables, graphs, and charts.
Some action verbs, such as “explain,” “describe,” or “interpret,” could be classified at different
DOK levels, depending on the complexity of the action. For example, interpreting information from a
simple graph, requiring reading information from the graph, is a Level 2. An item that requires
interpretation from a complex graph, such as making decisions regarding features of the graph that need
to be considered and how information from the graph can be aggregated, is at Level 3.
Level 3 Strategic Thinking requires deep knowledge using reasoning, planning, using evidence, and a
higher level of thinking than the previous two levels. The cognitive demands at Level 3 are complex and
1
abstract. The complexity does not result only from the fact that there could be multiple answers, a
possibility for both Levels 1 and 2, but because the multi-step task requires more demanding reasoning.
In most instances, requiring students to explain their thinking is at Level 3; requiring a very simple
explanation or a word or two should be at Level 2. An activity that has more than one possible answer and
requires students to justify the response they give would most likely be a Level 3. Experimental designs in
Level 3 typically involve more than one dependent variable. Other Level 3 activities include drawing
conclusions from observations; citing evidence and developing a logical argument for concepts;
explaining phenomena in terms of concepts; and using concepts to solve non-routine problems.
Level 4 Extended Thinking requires high cognitive demand and is very complex. Students are required to
make several connections—relate ideas within the content area or among content areas—and have to select
or devise one approach among many alternatives on how the situation can be solved. Many on-demand
assessment instruments will not include any assessment activities that could be classified as Level 4.
However, standards, goals, and objectives can be stated in such a way as to expect students to perform
extended thinking. “Develop generalizations of the results obtained and the strategies used and apply them
to new problem situations,” is an example of a Grade 8 objective that is a Level 4. Many, but not all,
performance assessments and open-ended assessment activities requiring significant thought will be at a
Level 4.
Level 4 requires complex reasoning, experimental design and planning, and probably will require an
extended period of time either for the science investigation required by an objective, or for carrying out
the multiple steps of an assessment item. However, the extended time period is not a distinguishing factor
if the required work is only repetitive and does not require applying significant conceptual understanding
and higher-order thinking. For example, if a student has to take the water temperature from a river each
day for a month and then construct a graph, this would be classified as a Level 2 activity. However, if the
student conducts a river study that requires taking into consideration a number of variables, this would be
a Level 4.
2
Table 1: Detailed Descriptors of Depth-of-Knowledge Levels for Science
(K. Hess, Center for Assessment, based on Webb, update 2005)
Level 1
Recall & Reproduction
a. Recall or recognize a
fact, term, definition,
simple procedure (such
as one step), or property
b. Demonstrate a rote
response
c. Use a well-known
formula
d. Represent in words or
diagrams a scientific
concept or relationship
e. Provide or recognize a
standard scientific
representation for
simple phenomenon
f. Perform a routine
procedure, such as
measuring length
g. Perform a simple
science process or a set
procedure (like a recipe)
h. Perform a clearly
defined set of steps
i. Identify, calculate, or
measure
Level 2
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
NOTE: If the knowledge
necessary to answer an item
automatically provides the
answer, it is a Level 1.
Skills & Concepts
Specify and explain the
relationship between
facts, terms, properties,
or variables
Describe and explain
examples and nonexamples of science
concepts
Select a procedure
according to specified
criteria and perform it
Formulate a routine
problem given data and
conditions
Organize, represent, and
compare data
Make a decision as to
how to approach the
problem
Classify, organize, or
estimate
Compare data
Make observations
Interpret information
from a simple graph
Collect and display data
NOTE: If the knowledge
necessary to answer an item
does not automatically
provide the answer, then the
item is at least a Level 2.
Most actions imply more
than one step.
NOTE: Level 3 is complex
and abstract. If more than
one response is possible, it
is at least a Level 3 and
calls for use of reasoning,
justification, evidence, as
support for the response.
Level 3
Level 4
Strategic Thinking
a. Interpret information
from a complex graph
(such as determining
features of the graph or
aggregating data in the
graph)
b. Use reasoning,
planning, and evidence
c. Explain thinking
(beyond a simple
explanation or using
only a word or two to
respond)
d. Justify a response
e. Identify research
questions and design
investigations for a
scientific problem
f. Use concepts to solve
non-routine
problems/more than one
possible answer
g. Develop a scientific
model for a complex
situation
h. Form conclusions from
experimental or
observational data
i. Complete a multi-step
problem that involves
planning and reasoning
j. Provide an explanation
of a principle
k. Justify a response when
more than one answer is
possible
l. Cite evidence and
develop a logical
argument for concepts
m. Conduct a designed
investigation
n. Research and explain a
scientific concept
o. Explain phenomena in
terms of concepts
Extended Thinking
a. Select or devise
approach among many
alternatives to solve
problem
b. Based on provided data
from a complex
experiment that is novel
to the student, deduct
the fundamental
relationship between
several controlled
variables.
c. Conduct an
investigation, from
specifying a problem to
designing and carrying
out an experiment, to
analyzing its data and
forming conclusions
d. Relate ideas within the
content area or among
content areas
e. Develop generalizations
of the results obtained
and the strategies used
and apply them to new
problem situations
NOTE: Level 4 activities
often require an extended
period of time for carrying
out multiple steps;
however, time alone is not
a distinguishing factor if
skills and concepts are
simply repetitive over
time.
3